Johnston writes of Bristol Palin's pregnancy

Levi Johnston writes in his upcoming book that his ex-girlfriend Bristol Palin was so angry about her mother's pregnancy with son Trig that she wanted to get pregnant, too.

(AP Photo/Matt Sayles, file) Levi Johnston arrives at US Weekly's Hot Hollywood party in West Hollywood, Calif. Johnston writes about his relationship with Bristol Palin and the Palin family in his upcoming book "Deer in the Headlights," set for release on Sept. 20.

Johnston says when Bristol found out her mother, former Alaska Gov. Sarah Palin, was expecting a baby she responded she should be having a baby, not her mother. He says she told him in March 2008, "let's get pregnant."

His book, "Deer in the Headlights: My Life in Sarah Palin's Crosshairs," comes out Sept. 20. The Associated Press bought a copy on Monday.

In Bristol Palin's own book, "Not Afraid of Life: My Journey So Far," released last June, she says she lost her virginity to Johnston on a camping trip when she got drunk on wine coolers.

Johnston, who has feuded often with the Palin family, says in his book if that's when Bristol first had sex, he "wasn't there." He says they did camp with friends but it was "well after" the two, who began dating in 2006, were sexually active. He says he remembers an instance in which Bristol wanted to get alcohol but he was against it because she would "lose her judgment" when drinking.

Johnston says he had "been too dumb" to use protection while dating Bristol but knew having a baby was "what she wanted."

Bristol Palin, who has been featured on ABC's "Dancing With the Stars," became pregnant at age 17 and had their baby at 18.

Johnston says when Sarah Palin first learned of the teen pregnancy she laughed, thinking it was a joke. He writes it was her husband, Todd Palin, who really showed his anger, raising his voice and telling him he needed to quit school and get a job.

Johnston claims Sarah Palin, a former GOP vice presidential candidate, also had an idea to adopt Bristol's baby to "avoid a scandal" but the young couple wouldn't allow it. Their son, Tripp, was born in December 2008.

Johnston says he and Sarah Palin were present for the birth but she said he wasn't there in a later interview, calling it "shameful." He also says she was adamant about not being called grandma, instead wanting to be called Mommy Sarah.

The relationship between Johnston and Bristol Palin ended shortly after the birth of their son.

Johnston says Bristol was moody before having Tripp and even more so after. He says she criticized how he handled their son and accused him of wanting her to look like a bad mom. He says Bristol also complained he was cheating on her.

In Bristol Palin's book, she says they broke up soon after their son's birth when she found a text on his cellphone indicating he was unfaithful.

The two reunited 18 months later and sold their engagement story to Us Weekly magazine.

Bristol says they broke up when he admitted getting another girl pregnant, which Johnston denies.

Sarah Palin skewered Johnston in her book "America by Heart: Reflections on Family, Faith, and Flag," writing that it was "disgusting" to watch him exploit his sudden fame after she was chosen as U.S. Sen. John McCain's running mate in the 2008 presidential election. She said he disgraced himself by repeatedly criticizing the Palins.